An x-ray of the newfound artifact revealed no such bodily bits, but it's possible that whatever was stored inside had long since decayed, Norton said.

The salt-glazed stone bottle is also stamped with the face of a grimacing man, possibly a likeness of the strongly anti-Protestant Cardinal Roberto Bellarmine (1542 to 1621).

Legend holds that Protestants smashed the jugs to defile the Catholic leader.

An engraving of a crowned lion, toward the base of the bottle, is likely the bottlemaker's trademark, he added.

Despite their name, witch bottles were more often intended as all-purpose lucky charms against bad luck, Norton said—"a modern equivalent of hanging a horseshoe on your door."

The superstitious also stuck children's shoes inside walls or buried horse skulls by doors—animals were believed to be able to see spirits, he said.

And though belief in magic has plummeted since the 1600s, there are still a few witches about. Some of them, Norton said, have found the bottle's discovery irresistible fodder for discussion in a few of the darker corners of Facebook.